Sealed switch



Jan. 16, 194,5. F. w. scHwlNN 2,367,441 i SEALED SWITCH Filed Aug. 6.1941 3 Sheets-Sheet 1 dafzy/@Jhz' @/m/law,

` @Wega Jan. 16, 1945.

F. w. scHwlNN l SEALED SWITCH Filed Aug. 6, 1941 3 Sheets-Sheet 3Patented Jan. 16, 1945 y PATE-NT oFFicEf SEALED SWITCH Frank W. Schwinn,Chicago, Ill.

Application August 6, 1941, Serial No. 405,589

' 4 Claims.

This invention `relates to improvements in weatherproof or sealedelectrical switches, and

more particularly concerns a switch having the contacts supported by andsealed within a hollow resilient body which is compressible to actuatethe contacts.

There has been a long-felt need for a practical, low cost simple switch,which canfbe made in small, compact sizes. readily adaptable to meet alarge variety of applications, and which is thoroughly and reliablysealed against the entrance of air, gas, vapors, moisture, liquids, dustor particles of foreign matter to the switch contacts,

and which might short-circuit, corrode, film, or

insulate the contacts, or be ignited by arcing at the contacts.

Switches have heretofore been proposed which are superflcially enclosedwithin a rubber sheath. That type of construction is generally notsatisfactory because of the diiilculty in securing a completely sealedcondition and the liability of the relatively rthin sheath becomingbroken or punctured and, further, because of the additional cost of thesheath. Such a switch, furthermore, retains all of the prior undesirablefeatures of metal springs and other delicate mechanism liable to breakor wear out, thus creating a high re` placement cost.

Another type of sealed switch has been designed for use in long lengthsas traffic switches to lie across the path of 4moving vehicles indriveways and streets for such purposes as controlling traiilc signals,alarms, or garage doors. The design of such trafiic switches has notbeen adapta ble to the held of small compact hand or mechanicallyactuated unit switches.

An objectl ofA this invention is to provide a sealed switch ofexceptionally simple, readily adaptable structure that may be producedin standardized small, compact form at low cost,

and which is eminently suitable for use in a great many places where acompletely protected, relatively easily operating switch is required.

Another object is to provide a switch of this kind that maybe moldedfrom compressible resilient insulating material, such as natural orarticial rubber, intov any of a wide variety of shapes and styleslhaving predetermined operating characteristics tomeet a largerange ofpractical applicaftions. ,4

My switch eliminates the use of small and delicate, trouble-making partsIand inits simplest form comprises only three parts, a hollowcompressible body and a pair of contact members which are mounted withinandsupported by the (C1. 20o-52)l body and movable into and out yofcontact by compression and expansion of the body.r The arrangement maybe such as to expose portions of the contact members to receive cur-rentconduct- 5 ing elements of an electrical circuit directly. For mostpurposes, however, leads may extend out from the contacts within thebody for connecting the switch in an electrical circuit exterlorly ofthe switch body. The engagement of the leads with the contacts is suchas to preclude uid leakage past the leads into the contact chamber.Thus, it is possible to produce the switch at very low cost butnevertheless of great reliability. 'Ihe manufacturing cost is so lowthat the switch can i5 be furnished for less than the cost of repairingmore complex types of switches.

Another feature of my invention is the utillzation in the operation of'the switch of not only the inherent resiliency of the material o! theswitch body but also of the pressure of gas trapped within thebodycavity in which the contacts are located.

yAnother object is to design a switch having a resilient body completelysealing the contacts and acting, when compressed, to carry the contactsinto rubbing engagement to assure a perfect electrical contact.

A further object is a weatherproof switch including a mountingpeculiarly adaptable to use with a bicycle stop light and to be mountedon a rear fork member of the frame to 'be actuated by the reaction ofthe coaster brake arm.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which simi larcharacters of referenice-y indicate similar parts throughout the severalviews.

Referring to the drawings:

Fig. 1 is a fragmentary view, in perspective, of the coaster brakeportion. of the rear wheel of a bicycle, and the rear fork and mud guardbraces, showing one ofy -my sealed switches in use as abrake-operated'signalswitch;

Fig. 2 is an enlarged end elevational view of Fig. 6 is a verticalsectional view through a mod ifled form oi the switch showing the switchbody in normal or distended condition;

Fig. 7 is a vertical sectional view of the switch of Fig. 6, showing thesame compressed to bring the switch contacts into engagement;

Fig. 8 is a perspective view showing the electrical contact members ofthe modified form of switch of Fig. 6;

Fig. 9 is a verticalsectional view through another modied form of theswitch;

Fh. l is a perspective view of the contact members of the modifiedswitch shown in Fig. 9.

Figs. 11 and 12 are vertical sectional views taken in a similar planethrough a further modifled form of the switch, the switch contacts beingshown in separated relation in Fig. l1 and in contacting relation inFig. l2;

Fig. 13 is a vertical sectional view showing still another modiicationof the switch, with the contacts separated: j

Fig. 14 is a vertical sectional View showing the switch of Fig. 13compressed to bring the contacts into engagement;

Fig. 15 is a perspective view of a doorbell switch constructionembodying the invention;

Fig. 16 is a vertical sectional view through the doorbell switch shownin Fig. 15;

Fig. 17 is a vertical sectional view through a modiiled form of thedoorbell switch; and

Fig. 18 is a vertical sectional view through another modied form of theswitch, which is of the normally closed type.

Referring to the drawings in detail, in Figs. 1 to 4, inclusive, isshown a preferred form of my switch, indicated generally by thereference numeral 2li, used as a water and dustproof stop signal lightswitch of a bicycle. Only fragmentary portions of the rear fork 2i andoi the rear mud guard braces 22, together with the coaster brake 23 andfragmentary portions of the spokes 24 of the bicycle are shown in Fig.l. as it. is believed that these few details will permit of fullunderstanding of this use of the switch without more elaborate showingof the remainder of the wellknown bicycle structure. The coaster brake23 has the usual brake arm 25, which is connected to the lower bar ofthe fork 2i by means of a metal strap 21 looped about the bar anddetachably secured tothe arm by means of a bolt 23.

The stop light (not shown) of the bicycle may be of any preferredconstruction and is considered, in the present instance, as operating ona single wire hookup wherein the mud guard braces 22 arecurrent-carrying parts of the light circuit.

The switch 20 comprises simply a small, slightly elongated hollow blockbody 29 `formed of a compressible resilient material enclosing a pair ofcontact members 30 and 3|. In the form shown, the body 23 is molded fromresilient rubb'er or equivalent material of suitable resiliency, havinga small, preferably central, cavity or chamber 32 which is of somewhatflattened form horizontally.

The contact members 30 and 3l may be iden-- tically formed from narrowstrips of electrical conducting material, such as brass, and extendlengthwise oi' the body 23 along the top and bottom walls of the cavity32. At their end portions the contact members are entirely embedded inthe material of -the body 23 at the opposite ends of the chamber 32. Thecenter portions of the contact members are bowedinvlrdlytopreamtcontactpointsu. Therubber of the body 29, interveningbetween the opvposed ends of the contact strips 30 and 3i, holds thecontact strips normally spaced apart.

Leading from either of the ends of the con tact strips 30 and 3i arewires 34 and 35, re-

spectively. The ends of the wires may be secured to the strips as bysoldering, and are preierably located on the opposite sides oi thecontact strips from the chamber 32. An insulating l0 sheath 3l surroundseach of the wires 34 and 35, and is preferably of a grade and type oirubber or other material which can be vulcanized ilrmly to the body 29.The inner ends of the insulating sheaths 31 terminate a substanaldistance from the chamber 32, and are thereby separated from the chamber32 by solid portions oi the body material. Thus, even though the sheathsmay accidentally be imperfectly vulcanized or even work loose, thesealed condition of the chamber 32 will remain unbroken.

In constructing the switch 2D, the body 2B may be initially molded asseparate upper and lower halves A and B, with the contact strips 33 and3i and the associated wires 34 and 35, respectively, and their sheathsmolded in place. The

halves of the body are then secured together permanently as byvulcanizing or cementing. In Figs. 3 and 4, the broken line C representsthe vulcanized or cemented joint between the two halves. In the separatehalves A and B, there will, of course, be shallow, matching depressionswhich combine to form the chamber 32 when the halves are securedtogether.

To close the contacts of the switch 20, the

35 upper and lower portions of the body 28 are squeezed together on anaxis of compression extending through the contact points 33 until thecontact points 33 interengage. In this, the portions of the body 23which deilne the side and end Walls of the chamber 32, being ofrelatively reduced mass compared with the top and bottom portions of thebody, will compress and dis tort more readily and thus facilitate quickcontacting of the contact points. It will be ob- 4,5 served that thecompact upper and lower opposed engagement faces of the body block arein more than projected co'extension with the maior or horizontal area ofthe chamber 32, so that when the upper and lower portions of the bodyare squeezed together by substantially over-al1 compressive engagementof opposed actuating members, the chamber is substantially ensmalled.

The side and end walls of the chamber 32 intersect the exure plane ofthe body 23 and 53 are formed concave in order to reduce distor- 50walls to bend easily as the top and bottom por- `tions of the body cometogether. As shown in Fig. 3, the concavity of the side walls preferablyextends laterally beyond the side edges of the contact strips 30 and 3|,thus further assuring freedom from possible interference by inwarddistortion of such walls. As a result of their con.- cave formation, theend Walls of the chamber 32, which extend between the anchored endportions of the contact strips 30 and 3| (Fig. 4),

tend to distort longitudinally outwardly of the body under verticalcompression and thus move away from the contact points 33.

The resiliency o1' the material of the body 23 acts when theswitch-closing pressure is released to return the body to theuncompressed or open switch condition. In addition, I may utilize thepressure of a compressed gas within the chamber 32 to assist in quickopening of the switch contacts upon release of the switch-closingpressure.I Any suitable gas may be utilized for this purpose but, as amatter of expediency and availability, the chamber 32 may be lled withair at ordinary atmospheric or higher pressure. As a result of theensmallment of the chamber 32 when the switch is compressed to closethe'contact points 33, not only is the material of the body compressed,but the gas within the `chamber 32 is also compressed by the closingtogether of the top and bottom walls of the contact chamber 32 andsupplements the resiliency of the lateral walls of the cavity in urgingthe body block back to normal shape, and thereby the contacts back totheir normal relative position. The compressed gas goes into the pocketswhich form at the ends and the sides of the chamber 32 by distortion ofthe concave end and side walls.

The arrangementA as shown in Fig. 1 is such that pressure for closingthe switch is created by any application of the coaster brake 23 to stopthe bicycle. For this purpose the switch is interposed between the loopof the anchoring strap 21 and the adjacent lower frame bar of the fork2|. The strap loop snugly embraces substantially the entire engagementface of the top and also the sides ofthe body 29. Slippage of the switchbody 29 from under the loop of the anchoring strap 21 is prevented byretaining beads 38 formed at the opposite ends oi' the body and spacedapart 'about' the same distance as the width of the strap.

A- saddle member 39 resting upon the fork bar provides a flat base underthe switch body. The saddle member 39 may be stamped from sheet metalshaped to provide integral right angular leg flanges 40 which are cutout to form aligned downwardly opening notches 4| yfor straddling thefork bar..y The sides of thelegs 40 extend laterally beyond the sideedges -of the body of the saddle and function as retaining ears .en-Agageable with the opposite edges of the anchor- `ing strap to avoidrelative displacement of the saddle and strap.

When the coaster brake 23 is applied, the simultaneous downward torqueexerted by the brake arm tends to rotate the latter counterclockwise sothat it pulls down upon the strap 21, thus compressing the switch body29 and rclosing the contact points 33. This completes the stop lightcircuit from a battery (not shown) through the wire 34, the switch 20,the wire 35, and the mud guard braces 22. An electrical connectionbetween the wir'e 35 and the mud guard braces is perfected through aneye terminal 42 on the wire which engages the braces where the latterare secured upon the rear wheel axle.

Promptly upon release of'the coaster brake, the rebound force which hasbeen created in the switch body 29 by its compression, returns the bodyto normal and thus raises the anchoring strap 21 and brake arm 25 toinitial position fromv from an insulating material, assures that theswitch will not short-circuit. The operation of the switch is smooth andpositive. Furthermore, no special structure or reconstruction of thecoaster brake is necessary to adapt the switch for operation by thecoaster brake. The only change in any conventional part of the coasterbrake assembly is in the arm-anchoring strap 21 which has a slightlylarger loop so as to accommodate the switch.

Although the switch 20 has been described as especially adapted for useas a bicycle stop light switch, it may obviously be used for otherpurposes where a completely sealed switch is necessary and where baseand vcompression members for operating the switch are available. It isadaptable for use in automobiles as a stoplight or starter switch, inautomatic machinery where protection is necessary against oil, cuttingagents, dust, and the like. Since it must withstand fairly strongpressure. sometimes of shock proportions as when the coaster brake` ofthe bicycle is jammed on, the switch 20 is of fairly compact andrelatively stiff construction. For some uses, the switch 20 maytherefore not be sufciently sensitive, that is, it may require greaterthan available force or pressure for operation. Because of its small,compact construction, this condition may exist even though the selectedgrade of rubber or other. resilient material may be as soft or flexibleas practicable.

I have accordingly provided a switch 43 (Figs.

6 and 7) which is designed for more sensitive the slight downwarddeilection resulting from the compression.

Because of its resilient action, the switch body 29 also acts to someextent as a shock absorber for the .coaster brake.

It will be apparent that the switch 20 is permanently sealed againstmoisture and dirt. This,

I taken together with the fact that the body 29 of operation. The switch43 has a hollow body 44 'provided with reasonably massive upper andlower portions joined together by comparatively much thinner and quiteflexible integral vertical walls 45. The hollow interior of the bodyserves as a sealed contact chamber 41. The inner f aces of the'walls 45may be concave as shown.

When pressure is applied, as for example-downwardly at the top of thebody 44, on an axis of compression as indicated by the` arrow at the topof Fig. 7, the thin walls 45 will distort readily and bulge out as seenin Fig. 7 .in 4a flexure plane intersecting the axis. Thus, little, ifany, compression of the more massive top and bottom portions of theswitch body is required to squeeze them together.

Compression of the switch body 44, as described, brings into engagementelectrical contact members 48 and 49 which are secured against the upperand lower walls, respectively, of the chamber 41. Inasmuch as the sides45 of the switch body 44 are of such limited thickness as may precludeproper anchoring of the contact members 48 and 49 laterally beyond thechamber 41, they are provided with upwardly and inwardly directed pairsof substantially L-shaped integral anchoring flanges 59 and 5I,respectively, which are embedded in the massive portions of the switchbody between the contact members and the opposite engagement faces ofthe body. The anchoring anges have their attached legs extendingvertically and the remaining legs lying horizontally within the thrustpath of the switchclosing pressure that is applied to the body 44.

lips.

form, as shown in Fig. 8, with the upper contact member 46 ofconcavo-convex shape. This permits the contact member 48 to make pointengagement with the contact member I9, even though pressure may beapplied unevenly to the switch body in closing the switch.

Electrical lead wires 62 and,63 are secured to the back faces of,respectively, the contact member lll and the contact member I9 as bymeans of soldering 64. The wires are encased in insulating sheaths55vulcanized within the body. The anchored end portions of the wires 52and 53 are received through apertures 51 in respective ones of theanchoring flanges'50 and 5I, and are thus positively engaged and heldagainst twisting or working loose from the contact members in themovement of the switch body incident to closing and opening of theswitch.

The external shape of the switch 43,may be square, round, or any otherpreferred shape, and the pressure faces (the upper and lower faces asviewed in Figs. 6 and 7) are preferably flat in order to facilitateengagement of the switch body between opposed members of an operatingmechanism.

For some purposes it may be desirable to have a fully sealed switch butin which direct engagement can be had with the contact membersexteriorly of the switch body, and thus avoid the use of lead wires.Such a switch, identified by the numeral 60, is shown in Fig. 9, and hasa compressible resilient body 6I enclosing a cavity 62 to providev achamber for upper and lower electrical contact members 63 and 64,respectively. The upper contact member 63 may be of concavo-convex formso as to make point contact with the lower contact member 64 when theswitch is closed. Each of the contact members has a pair ofsubstantially L-shaped anchoring flanges 65 which have their shorterlegs integral with the .respective contact members and their longer legslying in co-pianar edgewise abutting relation and provide pressureresistance reinforcements for the switch body block spaced from theupper and lower faces of the respective contact members. i

In order to permit a direct electrical connection with the contactmembers, the abutting long legs of the anchoring flanges 65 are exposedfiatwise to serve as friction terminals at the engagement faces of theswitch body 6I. Thus, the switch is adapted to be placed directly in aholder or clip between a pair of opposed current conducting elements,such as fingers 66 in an elec.- trical circuit, without requiringconnection of lead wires. This is of particular advantage in places-where replacement of the switch may have to be made with more or lessfrequency.

The fingers 66 of the switch holder may be in themselves resilient ormay be resiliently mounted to bear yieldably but firmly against `thefriction terminals of the switch 60.

In order to facilitate the insertion of the switch 60 and assurethorough electrical contact against the terminal faces thereof, theholder fingers 66 may be of slightly inwardly bowed shape and have theirfront ends formed as outwardly flaring The rear end portions of thefingers 66 are in the form of angular flanges which provide forwardlyfacing limit shoulders 66 for engagement by the opposing sides of theswitch body 6I. The rearwardly projecting portions of the angularflanges are connected, as by means of anchoring rivets 66h, 'to theopposite sides of an insulating base member 66C. Terminal screws 68d arethreaded into the rear anges for connecting the electrical lead wires oftheV circuit to the holder.

Where the insulating member 6Ic is resilient, the entire holder may besqueezed to actuate the switch. On the other hand, the fingers 66 may beof such flexibility that they can be directly y fiexed'inwardlysufficiently to compress the switch body 6l and actuate the contacts 63and 6l.

The contact chamber 62 has the thin side walls concave in order toreduce strain and assureoutward distortion or buckling of these wallswhen the switch body is compressed to close the contacts 63 and 64. Atthe top and bottom of the side walls, the material of the switch body Il,preferably extends into overlapping relation to the contact faces ofthe respective contact members, as indicated at 61, in order to effect aseal against leakage due to possible loosening of the body material fromthe outside vertical faces of 4the short legs of the anchoring flanges65 which extend to the outside of the switch body.

Where it is desirable to have a rubbing engagement between the contactsof the switch, either the modified form of switch 1li shown in Figs. l1and 12, or the modified switch 1l shown in Figs. 13 and 14, may be used.

The switch 10 comprises upper and lower relatively massive body portions12"and 13, respectively, of substantially triangular shape joinedtogether in spaced relation by relatively thin, interiorly concaveintegral walls 14 which seal the space between the body portions to forma chamber 15. The chamber is of flattened shape and lies at an obliqueangle with relation to the upper and lower, preferably fiat, horizontalengagement faces of the switchbody. Upper and lower obliquely tiltedelectrical contact members 11 and 18 are supported by the body portions12 and 13, respectively, in opposed normally spaced rela tion on the topand bottom walls of the chamber 15.` The upper contact member 11 mayhave a convex contact face for point engagement with the face of thelower contact member 18.

Each ofthe contact members is anchored in its respective supporting bodyportion by means of a pair of anchoring flanges 19 and 80 embeddedtherein. In each instance, the anchoring flange 19 is relatively shortand extends inwardly from that portion of the edge of the associatedcontact member which is located nearest the adjacent engagement face ofthe switch body.

.The flanges are of sufficient length to extend vertically from theremote edges (considered with respect to the horizontal engagementfaces) of the respective tilted contact members to points opposite theanchoring flanges 19 and have short legs 8| directed edgewise toward,but in spaced. co-planar relation to the flanges 19. Thus, the anchoringflanges are interposed between the contact members and the engagementfaces of the switch body and receive equally the compression thrust towhich the switch body is subjected in closing the contacts. Electriclead wires I2, encased in insulating sheaths 63 vulcanized'to the switchbody, may extend through apertures Il in the anchoring flanges 80adjacent the horizontal flange legs 8l and are soldered to the innerfaces of such legs.

When the switch 10 is compressed to close the contacts, as by downwardvertical pressure upon the upper face of the switch body on a centralaxis of compression, as indicated by the arrow at the top of Fig. 12,the side walls 14 yield by bowing outwardly until the contact member 11engages' the inclined contact face of the member contacts and assures apositive electrical connection.

Whereas the switch is designed for a relatively small range of movementbetween the contact members in an angular path, the switch 1| isdesigned for somewhat greater, but rectilinear relative movement betweenthe contacts. In the switch 1|-, the compressible resilient body hasupper and lower relatively massive body portions 85 and 81,respectively, provided with flat, parallel exterior engagement faces.The portions 85 and 81 are spaced substantially apart by relativelythin, interiorly concave, integral side walls 88 sealing a contactchamber 89. At the top of the chamber 89 the upper portion 85 of theswitch body supports a contact member 90 provided with a downwardlyprojecting boss or contact Ahea-d 9| of preferably bulbous shape. Anupwardly opening socket 92 formed in a lower contact member 93 supportedat the bottom of the chamber 89 is designed to receive the contact Fig.14, the side Walls 88 become distorted and bow outwardly and the bodyportions k85 and 81 approach until the contact head 9| Ienters thecontact socket 92. The outer transverse dimen sion of the head 9| ispreferably slightly larger than the inner transverse dimension of thesocket 92 so that the heady 9| will enter the socket with a frictional,rubbing action that assures thorough electrical contact between the twocontact members. The Walls of the socket 92 may be formed to yieldslightly when the head 9| enters it.

Connection of the switch 1 in anv electrical circuit exteriorly of thebody of the vswitch may be effected through electrical leads 98 and 91which have their ends soldered to the anchoring flanges 94 and 95 of therespective contact members.

In Figs. and 15 is shown a modified form4 lov |00 of my switchparticularly adapted for use as 'I a door bell or annunciator switch.One of the principal sources of trouble with door bell switches arisesfrom snorting of the circuit byv entrance of moisture to the switchcontacts. l 1nasmuch as the contacts in my switch are completely sealedwithin the Waterproof body, such trouble is avoided.

The switch |00 comprises a flat, hollow rubber l Contact The wausof thecavity at the-sides and' between the embedded end portions of the:con-'- tact members are preferably concave as in the previouslydescribed forms. Lead wires |08are secured to the opposed ends adjacentone side of the body |0|, with their rubber sheathing L09 vulcanized inthe body.. The leads may extend from the switch through -a hole 0 boredthrough the jamb |02.

Compression against the switch -body |0| to close the contact point |01is effected by a push button bearing against the outer face of the body|0| and held in place by a centrally perforated, laterally flangedretainer casing or housing shell ||2. The housing shell may be securedto the jamb |02 by means of washerhead screws H3. It will be clear lthatregardless of the exposure of the switch |00 to the elements, moisturecannot disrupt the electrical circuit at the switch.

In the modified form of door bell switch ||4 shown in Fig. 17, thefunctions are substantially like the switch |00, but the switch is madeto avoid the need for a housing shell or separate push button. Theswitch 4 includes `a body of compressible resilient material having acavity ||5 which houses opposed, normally spaced contact members ||1 and8. The rear face of the switch body is fiat and is adapted to restagainst a door jamb or the like (not shown). Lead wires ||9 by which theswitch ||4 is connected in an electric bell or annunciator circuitextend from the contact members ||1 and ||8 out off the switch bodythrough a recess in the rear face of the body.

' In this form, the switch body has an integral lateral flange |2|provided with holes |22 to receive the screws for securing the switch tothe door jamb. In addition, the switch ||4 has molded integrally at thecenter of its front face, a boss |23 serving as a push button.

'Ihe door bell switch ||4 is inexpensive to make and since it is allformed in one piece, eliminates separable parts that might become lostprior to installation of the switch. Since all parts of the switch body,including the push button and the attaching flange, are formed of thesame weather-resistant material, it will uniformly resist weathering andis free from the deteriorating effect of corrosion which attacksswitches having exposedmetallic parts.

The switches thus far described have all been ofthe normally open style,that is, the embedded contacts are held apart by the material of theswitch body in the extended or non-compressed condition of the switch,and are carried into switch closing engagement by the squeezing towardone another ofthe opposite contact carrying portions of the switch body.For some purposes it may be necessary to have al normally closed switchwhich may be selectively opened Aby the squeezing of the switch body. Anexample of such a normally closed switch, identiiied generally by thenumeral |25, is shown in Fig. 18.

The switch\|25 comprises a body of resilient, compressible material andincludes relatively thick head and base portions |26 and |21,respectively, which are integrally connected together by side walls |28which hermetically seal a contact chamber |29. The inner faces of thewalls |28 may be concave, as shown.

Normally closed contact members |30 and |3| are carried by the head |28and the base |21, respectively. Each of the contact members ispreferably of substantially U-shape construction, having one legembedded in the respective sup- Dorting member parallel to thepreferably hat engagement face oi such member. The web portions of thecontact members extend into the chamber |29 at diametrically oppositesides, and the remaining legs |32 and |33 of the contact members extendinto overlapping engagement inside of the U of the respectively opposedengagement member. The contact leg |32 may be bowed toward the contactleg |33, as indicated at |34, in order to assure thorough electricalcontact therewith. Preferably, the contact legs |32 and |33 are sorelated that in the noncompressed condition of the switch, they bearagainst one another with sufcient opposing pressure to maintain e, ilrmengagement.

In the operation of the switch |25, squeezing pressure is exertedagainst the head and base portions |20 and |21 which carries them towardone another and causes the contact legs |32 and |33 or! the contactmembers to separate, thus opening the switch. At the same time theconcave lateral walls |28 distort outwardly away from the` contactmembers.

Electrical connection of the contact members |30 and |3| is effectedthrough the medium of electrical leads |35 and |36, respectively. Theleads extend through the respective side portions of the body adjacentthe webs of the contact members and through the webs and are anchored tothe embedded legs of the contact members by means of solder or the like|31. The insulating sheaths |38 of the leads |are preferably moldedwithin the material of the body.

In all forms of my switch, the contacts are completely enclosed withinthe dust-proof, sparkproof and fluid-proof body. The compressible,resilient material of the body may be selected for the particularqualities of resiliency and resistance to water, oil or chemicals, bestadapted for the use to. which the switch is to be put. For example, anordinary grade of natural .rubber may be suitable for uses where theswitch is merely to be exposed t the weather as for example in the taillight switch 20 or the doorbell switches |00 and H4. But when the switchis to be used in places where natural rubber will not stand up becausesubject to oil or certain gases or strong chemical solutions as inprocessing tanks, appropriate types and grades of synthetic rubber may-be used. Hence, the term rubber" where used in the claims is intendedto be given a generic meaning, including both natural rubber and thesynthetic or so-called rubber substitutes suitable for the presentpurpose. In addition to the several uses Specifically illustrated ormentioned, there are of coursev many other uses rior which my switchesare emisulating sheaths.

nently suitable. The switches may be formed in an innite variety ofshapes to fit practically any mechanical environment and can actually bemade to ilt in places where it is difficult or impossible to putordinary switches.

Although not specifically mentioned in every instance herein, Icontemplate that all of the described forms of switch or their variantsmay be filled with a gas (air being the form most likely used) ,undernormal atmospheric or higher pressure which will be compressed when theswitch is closed and thus assist in opening the switch. Each form of theswitch, it will also be noted, preferably has the walls o! the contactchamber of more or \less concaveform fior the An advantage of havingthecontact chambers of the switchesgas filled is that duringcomprespurposes described in connection with the switch" sion of theswitches the pressure created by the compressing of the gas pushes thewalls of the chambers laterally outwardly away from the portions of thecontacts that are exposed within the chambers. This avoids any tendencyof the material of the walls to bend inwardly into interferring relationwith the contacts when the switch are flexed during operation of theswitch.

It will be observed that in each of the forms of the switch that haslead wires extending from the contacts and out through the material oithe body, the relationship oi' the lead wires is such as to move freelywith the associated parts of the switch and avoid pulling or twistingstrains whichmight tend to loosen the wires or their in- 'Ihat is, thewires extend laterally of the direction of.movement of the main parts ofthe switch. Thus, where the movement is vertical, the wires extend fromthe massive portions of the switch body in horizontal directions eitherfrom the same side of the body (Figs. 4, 6, 13, 16 and 17) or fromopposite sides (Figs. 11 and 18).

Instead of simple contact members of the types illustrated, over-centeror eccentric mechanical contact arrangements can be secured within thesealed cavity of the switch body to provide a switch that will remain inclosed condition after actuation and until reactuated to release thecontact mechanism.

While the invention is susceptible of various modifications, andalternative constructions, I have shown in the drawings, and have hereindescribed in detail certain preferred embodiments, but it is to beunderstood that I do not thereby intend to limit the invention to thespecific forms disclosed, but intend to cover all modifications andalternative constructions falling within the spirit and scope of theinvention as expressed in the following claims.

I claim:

1. In combination in an electrical switch construction of the characterdescribed adapted for controlling a bicycle stop light circuit, a hollowbody of compressible resilient material having a pair of normally spacedelectrical contacts therein, a base member adapted to be mounted uponthe bicycle frame and providing a broad supporting surface for saidbody, and a looped member engaged over said body and extending past saidbase member for connection to the torque arm of the bicycle coasterbrake so that when the coaster brake is applied the looped member willpull against and compress the body, thus closing said contacts, theresiliency of said body being such that the body normally returns to anuncom- Pressed condition, carrying said looped member along, uponrelease of the pulling force from said looped member.

2. A switch construction substantially as set forth in claim 1, whereinsaid body carries means for engagement with said looped member to holdsaid body in place'.

3. A switch construction substantially as denned in claim 1, wherein thebase member carries means engageable with the looped member to .hold thebase member in place` with respect to the` switch body and theassociated part of the bicycle frame.

4.' 'In a sealed switch unit adapted for actuation by an externalmovable member, a block of resilientrubber constituting a body having acavity therein formed to provide an axis of compression extendingthrough the cavity. and presenting exposed faces intersected by the axisfor compressive engagement by the actuating member, rigid electricalcontact means within the cavity adapted for relative movement into andout of contacting relation, said contact means including a sheet metalcontact member having an anchoring element extending from one sidethereof embedded in said body at the walls of the cavity nearest saidexposed faces ot the body and extending vas a thrust resisting`reinforcement into the material of the body between the contact memberand said face, whereby compression of the body. by said actuating memberacting against said exposed face will also move said contact member,said anchoring element being of substantially L shape, having anapertured leg integral with the contact member and extending therefromtoward the exposed engagement face f of the body, and the other legbeing directed into being anchored in electrical communication withs'aid contact member.

FRANK W, SCHWIN'N.

